Diversity of Aquatic Actinomycetes in Lakes of the Middle Plateau, Yunnan, China

A total of 749 sediment and water samples were collected from 12 lakes of the Middle Plateau of Yunnan from 1983 to 1993. The diversity and biological characteristics of the aquatic actinomycetes in these lakes were studied. Sixteen genera of actinomycetes were isolated from these samples. Micromonospores assumed a notable dominance (from 39 to 89%) in the actinomycete populations of these lake sediments. Streptomycetes were the second most abundant organisms. The diversity and counts of actinomycetes varied with the season. Thermophilic actinomycetes have a wide distribution in these lakes, but their counts were smaller. The cell wall compositions of certain Micromonospora and Streptomyces strains from an alkaline lake revealed an unusual combination of glycine and isomers of diaminopimelic acid. It seems that aquatic actinomycetes play a significant role in the decomposition of organic substances, including some toxic compounds such as phenol, in these lakes. It also appears that aquatic actinomycetes are one of the important resources for screening useful enzymes and metabolites.     

辐射污染区土壤中放线菌的分离及多样性

从辐射污染区采集42份土样, 分别采用6种分离培养基进行放线菌的分离, 共获得152株放线菌。经形态、核糖体DNA扩增片段限制性内切酶(Amplifed ribosomal DNA restriction analysis, ARDRA)分析比较, 选取其中的60株进行16S rRNA基因测序。通过序列比对、聚类分析, 60株菌分布在放线菌纲中的12个属, 链霉菌属占大多数, 有大量稀有放线菌, 这表明辐射污染区具有较丰富的放线菌属种多样性。     

酸性土壤中嗜酸稀有放线菌的多样性研究

从江西、云南、北京采集的10份酸性土样中分离出嗜酸放线菌252株,其绝大部分为链霉菌。通过形态观察、pH梯度生长实验和细胞壁化学组分分析筛选出稀有放线菌代表菌株20株。ARDRA分析表明,它们呈11种不同的图谱类型,其中9株的图谱相同,另外4株的图谱与之差异不大,而其余7株的图谱与之差异很大且各不相同。16S rDNA序列分析表明,20株稀有放线菌中的18株分别属于6个已知属,其中13株属于诺卡氏菌属(Nocordia),它们在系统发育树上处于多个进化分枝;各有1株分别属于壤球菌属(Agrococcus)、节杆菌属(Arthrobacter)、北里孢菌属(Kitasatospora)、考克斯菌属(Kocuria)和嗜酸链霉菌属(Streptacidiphilus);其余2株是迄今尚未定名的一个新科(“Ellin5034 group”)中的成员。实验结果显示,酸性土壤中的嗜酸稀有放线菌具有较丰富的种属多样性,其中诺卡氏菌属(Nocardia)是一优势菌群。     

云南西北部植被多样性特征分析

滇西北指云南西北部,其北面和东面分别与青藏高原和川西南相连.狭义的的划分仅指丽江-维西一线以北,横断山脉的中北段,包括中甸北部和德钦,平均海拔4 000m左右,属于青藏高原的东南部分,位于我国大地势结构的第一级阶梯.这一区域中,南北向的高山峡谷相间排列,而且排列最为紧密(怒江至金沙江最短间距仅为60km)、地势起伏最大(地面切割深度超过2000m),形成举世瞩目的“三江地区”的一部分.长期以来,“三江地区”因其独特的自然景观、丰富的生物多样性和重要的生态保护价值,成为世人研究和探寻的热点.     

云南省高等植物多样性与分布状况

云南省为我国乃至世界生物多样性的热点区域之一.为深入认识和保护云南的植物多样性,作者以《云南植物志》为基础,对其中记载的各物种在云南的县级分布情况进行了统计.结果显示:云南省高等植物多样性最丰富的为滇西北地区,其中的玉龙县、贡山县、香格里拉县物种数分别高达4,358种、3,981种和3,874种,其次为以西双版纳州为主体的南部热带边缘,其中的勐腊、景洪的物种数也都在3,000种以上;而以云南高原为主体的滇东和滇中地区植物多样性则较为贫乏,作者认为这与人们的关注度和野外调查的强度直接相关.云南分布有4,008种特有物种,4,509种狭域物种,特有物种的分布规律与总物种相似;含狭域物种最多的为贡山县(556种),是唯一超过500种的县.云南省多数物种的分布范围极为狭窄,64.1％的物种仅分布在1-5个县,46.0％的特有物种只分布在1个县的范围内.通过以上分析,作者指出由于此前对云南植物多样性的调查仍不完善,结果并不能全面反映真实的地带性规律,建议加大调查深度和标本采集量.如果条件许可,一些极易沦为濒危种的狭域分布种也应得到优先关注.     

新疆塔里木盆地可培养嗜盐放线菌系统发育多样性

应用纯培养手段和基于16S rRNA基因序列的系统发育分析,对从塔里木盆地高盐环境土壤样品中分离的18株可培养嗜盐放线菌多样性进行了研究.实验结果表明,18株嗜盐放线菌可3个(GlycomycetaceaePseudonocardineae和Nocardiopsaceae),在有效发表的5个属的嗜盐放线菌中有4个属的嗜盐放线菌被分离到.多数菌株属于Actinopolyspora属(38.9%),Nocardiopsis属(27.8%)和Streptomonospora属(22.2%),是塔里木盆地高盐环境中嗜盐放线菌的优势类群.这些分离菌株中,菌株YIM 92370与最近种的相似性为92%,在Glycomycetaceae科内形成一个独立的分支,极有可能代表Glycomycetaceae科的一个新属.研究结果表明塔里木盆地高盐环境中存在有较为丰富的嗜盐放线菌系统发育多样性,并且潜藏着新类型的放线菌资源.     

Acidophilic Soil Actinomycetes

A clear-cut dependence of the distribution of acidophilic actinomycetes on the pH value of soil was established. Acidophilic actinomycetes were found to be present in soils whose pH does not exceed 6.8 (acid forest soils, lowland peaty soil, and ordinary chernozem) and not in slightly alkaline soils (chestnut sodic and alluvial meadow soils). In acid lowland peaty soil, the species diversity of acidophilic streptomycetes was lesser than the species diversity of streptomycetes revealed in the same soil by using neutral medium.     

Alkaliphilic Soil Actinomycetes

The actinomycete complex of alkaline soils was found to be dominated by alkaliphilic streptomycetes, which showed maximal radial rates of colony growth at pH 8. At pH values of 7 and 10, the growth of these streptomycetes was poor. Alkaliphilic streptomycetes can be morphologically differentiated from other actinomycetes based on their high radial rates of colony growth and increased spore formation in alkaline media as compared to neutral media.     

云南茶树上的附生地衣

对云南茶叶农场中的附生地衣进行调查发现:附生在茶树上的地衣有25属,51种;其中,45种是首次报道附生在茶树上,包括2个中国新记录种:癞屑衣(Lepraria lobificans)和阿曼原胚衣(Protoblastenia amagiensis),以及加个云南新分布种.壳状地衣的共生菌丝侵入茶叶树干外皮层组织,在牛长过程中产生地衣酸,一定程度的加速了农场中茶树的老化;靠近茶树发芽点生长的壳状地衣和叶状地衣,造成芽体发育不良,对茶叶的产量和品质有一定影响.     

云南茶树上的附生地衣

对云南茶叶农场中的附生地衣进行调查发现: 附生在茶树上的地衣有25 属, 51 种; 其中, 45 种是首次报道附生在茶树上, 包括2 个中国新记录种: 癞屑衣( Lepraria lobificans) 和阿曼原胚衣( Protoblastenia amagiensis) , 以及20 个云南新分布种。壳状地衣的共生菌丝侵入茶叶树干外皮层组织, 在生长过程中产生地衣酸, 一定程度的加速了农场中茶树的老化; 靠近茶树发芽点生长的壳状地衣和叶状地衣, 造成芽体发育不良, 对茶叶的产量和品质有一定影响。     

植物内生放线菌多样性研究进展

植物内生放线菌作为植物内生菌资源的一大类,具有丰富的多样性,其次级代谢产物也十分丰富,而且还具有各种生物学活性。通过了解植物内生放线菌资源的多样性,可以对其产生的生物活性物质进行筛选和分析,从而筛选出具有良好药理活性的物质应用于临床。从植物内生放线菌宿主植物、组织分布、种类和数量以及活性基因4个方面综述了植物内生放线菌的多样性资源,介绍植物内生放线菌新的微生物物种,总结了植物内生放线菌目前研究中存在的问题及展望。     

云南西北部地区地表甲虫的物种多样性

共调查了云南西北部地区的中甸大雪山、中甸碧塔海、德钦白芒雪山、丽江石鼓镇、玉龙雪山保护区和永胜县6个小区域。采用巴氏罐诱法研究不同生境下地表甲虫物种多样性的变化。其结果：①共采集甲虫标本2852号,分属16个科,以隐翅虫数量最多,占41.3%;步甲次之,占25.9%;金龟、象甲、拟步甲的数量各占5％以上;其他11科合计占13％;②甲虫群落的物种多样性分析表明：农业活动频繁的永胜县,个体数量和丰富度较低;游牧业和旅游业频繁的中甸碧塔海多样性指数和丰富度较低;其他4个区域多样性指数、均量和丰富度较低;游牧业和旅游业频繁的中甸碧塔海多样性指数和丰富度较低;其他4个区域多样性指数、均匀度指数、丰富度以及个体数量比较均匀。除永胜县外,其他地区甲虫群落间相似性系数随空间距离的增大而降低。③比较针叶林、阔叶林、混交林、灌丛和草甸等5种生境,所有甲虫、步甲、金龟数量在针叶林和草甸生境内较高;隐翅虫数量在针叶林和阔叶林内较高;象甲在阔叶林内数量较高;拟步甲在灌丛内数量较高;但只有步甲和隐翅虫差异显著。④物种的个体数量、丰富度和多样性指数随海拔高度不同,其变化趋势相似。在1500－2000m呈下降趋势;在2500－3000m和3500－4000m分别形成2个峰值。均匀度指数的变化趋势则与之相反。以上结果表明,空间距离和生境类型影响云南西北部地区地表甲虫群落的物种多样性和相似性,频繁的农牧业和旅游业活动,对保持地表甲虫物种多样性的自然分布规律产生一定影响。     

The Diversity and Anti-Microbial Activity of Endophytic Actinomycetes Isolated from Medicinal Plants in Panxi Plateau,China

Traditional Chinese medicinal plants are sources of biologically active compounds, providing raw material for pharmaceutical, cosmetic and fragrance industries. The endophytes of medicinal plants participate in biochemical pathways and produce analogous or novel bioactive compounds. Panxi plateau in South-west Sichuan in China with its unique geographical and climatological characteristics is a habitat of a great variety of medicinal plants. In this study, 560 endophytic actinomycetes were isolated from 26 medicinal plant species in Panxi plateau. 60 isolates were selected for 16S rDNA-RFLP analysis and 14 representative strains were chosen for 16S rDNA sequencing. According to the phylogenetic analysis, seven isolates were Streptomyces sp., while the remainder belonged to genera Micromonospora, Oerskovia, Nonomuraea, Promicromonospora and Rhodococcus. Antimicrobial activity analysis combined with the results of amplifying genes coding for polyketide synthetase (PKS-I, PKS-II) and nonribosomal peptide synthetase (NRPS) showed that endophytic actinomycetes isolated from medicinal plants in Panxi plateau had broad-spectrum antimicrobial activity and potential natural product diversity, which further proved that endophytic actinomycetes are valuable reservoirs of novel bioactive compounds.     

Crop Genetic Resources Diversity and Sustainable Agriculture in Yunnan Province,China

Yunnan is well known as a "Kingdom of Plant". Yunnan is also rich in natural resources of crop. Lots of studies on collection, conservation, protection, evaluation and utilization of crop genetic resources have been done in recent years. But there are some unfavourable factors, too. With the agricultural intensity, some new problem such as decreasing diversity, simplifying varieties and narrowing genetic basis of crop have arisen to restrict the development of agriculture in Yunnan. The only way to achieve a sustainable agriculture in Yunnan is doing our utmost to protect the crop diversity, develop new crop or new varieties and widen the genetic basis of crop varieties.     

云南金平分水岭国家级自然保护区苔类植物物种多样性

自2015年至2018年对云南金平分水岭国家级自然保护区的苔藓植物进行野外考察、标本采集及鉴定,统计该地区苔类植物34科60属203种(含种下分类单元)。对自然保护区苔类植物物种进行多样性分析,结果显示,细鳞苔科(57种)和羽苔科(34种)所包含物种数量最为丰富;平铺型是本调查区的优势生活型类型;从物种的区系组成来看,广义的热带成分比重最大,达40.4%。     

Diversity of culturable ericoid mycorrhizal fungi of Rhododendron decorum in Yunnan, China

The diversity of ericoid mycorrhizal fungi isolated from Rhododendron decorum Franch. in Yunnan, southwestern China, was examined for the first time. In total 300 hair-root samples were collected from 13 R. decorum individuals in two adjacent wild population sites and one cultivated population site. Two hundred eighteen slow-growing isolates were obtained; the ability of some to form ericoid mycorrhiza was tested in vitro. One hundred twenty-five isolates formed hyphal structures morphologically corresponding to ericoid mycorrhiza, and these were determined by morphological and molecular means to belong to 12 fungal species. There were hardly any differences in species among the three sampled populations. The sequences of several isolates were similar to those of Oidiodendron maius and ericoid mycorrhizal fungi from Helotiales, accounting respectively for 18.4% and 24.8% of the total culturable ericoid mycorrhizal fungi assemblage. Dark septate endophytes were detected in the sampled hair roots by microscopy.     

新疆南部土壤放线菌区系研究

从新疆南部巴州和克州两地区8个县(市)采集农田、原始森林、草甸、戈壁、荒漠和盐碱土壤51份,使用6种分离培养基,9种分离方法分离,并对分离得到的放线菌进行了鉴定。共得到9个属的放线菌,其中链霉菌为优势菌,并可分为13个类群。同时,较为全面、系统地研究了两地区之间和不同类型土壤中放线菌区系组成和异同。     

Diversity of Actinobacterial community in saline sediments from Yunnan and Xinjiang, China

The diversity and community structures of actinobacteria in saline sediments collected from Yunnan and Xinjiang Provinces, China, were investigated with cultivation and 16S rRNA gene analysis. A total of 163 actinobacterial isolates were obtained, and they were affiliated with the order Actinomycetales (distributed into five suborders: Streptosporangineae, Micrococcineae, Streptomycineae, Pseudonocardineae, and Glycomycineae). A total of 748 actinobacterial 16S rRNA gene clones were examined, and they could be classified into Actinomycetales, Acidimicrobiales, and unclassified actinobacteria. The Actinomycetales sequences were distributed into nine suborders: Streptosporangineae, Glycomycineae, Micromonosporineae, Pseudonocardineae, Corynebacterineae, Frankineae, Propionibacterineae, Streptomycineae, and Micrococcineae. The unclassified actinobacteria contained three new clusters at the level of subclass or order. Our 16S rRNA gene phylogenetic data indicated that actinobacterial communities were very diverse in the investigated saline sediments (salinity 0.4–11.6%) and some actinobacterial members may be halotolerant or halophilic. The actinobacterial community structures in the saline sediments were different from those in marine and freshwater environments. Our data have implications for a better understanding of the distribution of Actinobacteria in saline environments. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Diversity of Fungi, Bacteria, and Actinomycetes on Leaves Decomposing in a Stream

Although fungi, bacteria, and specific bacterial taxa, such as the actinomycetes, have been studied extensively in various habitats, few studies have examined them simultaneously, especially on decomposing leaves in streams. In this study, sugar maple and white oak leaves were incubated in a stream in northeastern Ohio for 181 days during which samples were collected at regular intervals. Following DNA extraction, PCR-denaturing gradient gel electrophoresis (DGGE) was performed using fungus-, bacterium-, and actinomycete-specific primers. In addition, fungal and bacterial biomass was estimated. Fungal biomass differed on different days but not between leaves of the two species and was always greater than bacterial biomass. There were significant differences in bacterial biomass through time and between leaf types on some days. Generally, on the basis of DGGE, few differences in community structure were found for different leaf types. However, the ribotype richness of fungi was significantly greater than those of the bacteria and actinomycetes, which were similar to each other. Ribotype richness decreased toward the end of the study for each group except bacteria. Lack of differences between the two leaf types suggests that the microorganisms colonizing the leaf biofilm were primarily generalists that could exploit the resources of the leaves of either species equally well. Thus, we conclude that factors, such as the ecological role of the taxa (generalists versus specialists), stage of decay, and time of exposure, appeared to be more important determinants of microbial community structure than leaf quality.